发明名称 Wide angle lens system having short overall length
摘要 This invention relates to a wide angle lens system having small telephoto ratio. The strong curvature of a negative lens group arranged on the image side, which is the characteristic of the lens system of this type, is eased by composing the negative lens group as a doublet. This structure maintains the spacing between the front lens group and the rear lens group to be small. The negative lens group on the image side comprises two negative meniscus lenses, which have surfaces having stronger curvature facing each other.
申请公布号 US4673259(A) 申请公布日期 1987.06.16
申请号 US19860838836 申请日期 1986.03.12
申请人 RICOH COMPANY, LTD. 发明人 KAWAMURA, ATSUSHI
分类号 G02B9/34;G02B9/60;G02B13/02;G02B13/04;(IPC1-7):G02B9/60 主分类号 G02B9/34
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